Drug gives hope to pet owners

Trials aim to help cats, dogs with kidney disease

May 22, 2001|By Carlos Morales, Tribune staff reporter.

When Dr. James N. MacLeod presents his paper Friday on a new drug for a complication of chronic kidney disease to the American College of Veterinary Internal Medicine in Denver, the Cornell University researcher is likely to be deluged with feline volunteers for a clinical trial of a promising new treatment.

"It will open the floodgates," MacLeod said last week.

Until then, MacLeod will monitor the progress of Boomer, a 13-year-old Persian from Orland Park. With approval from the Food and Drug Administration, Boomer is the first cat outside Cornell's Ithaca, N.Y., laboratories to receive the trial drug.

For the last five months, Boomer has been through a medical wringer of traditional treatments for chronic kidney disease, all with little success. But last week Boomer's owners placed their hopes for the 17-pound male in a test of the new medicine.

Like most clinical trials involving humans or animals, availability to the public of any new drug can be years away. But if Boomer improves, the implications could be huge, because chronic kidney disease is the No. 1 health problem in older cats, said Flossmoor veterinarian Michele Gaspar, Boomer's doctor. The disease is common in dogs too.

"The approval process for a new companion animal drug is similar to the approval of a new human drug," said Melanie Berson, director of the Division of Therapeutic Drugs for Non-Food Animals within the FDA's Center for Veterinary Medicine. "The major difference is that the size of the clinical trials for animal drugs is many times smaller."

A human clinical trial typically involves thousands of test subjects; an animal trial involves only hundreds, Berson said.Cynthia Labriola and Jim Devlin of Orland Park knew something was wrong late last year when Boomer, who usually greets the couple at the door and shadows them around the house, became lethargic, hardly ate and started drinking lots of water.

The couple took Boomer to Gaspar at the Cat Clinic, where his condition was diagnosed in November as chronic kidney disease.

Gaspar advised the couple to take Boomer to a veterinary teaching hospital at the University of Wisconsin in Madison, but after three days of fluid treatments there, separation anxiety necessitated ending Boomer's stay.

"We love this cat and we want him to be comfortable. We want him to be with us for a while yet," Labriola said.

In January, Gaspar began treating Boomer with a drug for human kidney disease that's used to stimulate production of red blood cells in patients who are anemic from the illness.

But about 30 percent of cats, like Boomer, develop antibodies to the human drug. In such cases, treatment with the human drug must cease--Boomer's treatment ended in April--leaving only the options of repeated blood transfusions or euthanasia. Boomer had one blood transfusion three weeks ago.

But earlier this month Gaspar came across medical literature about a study being conducted at Cornell involving cats and dogs with chronic kidney disease.

Gaspar got in touch with MacLeod, associate professor of molecular genetics at Cornell's Baker Institute for Animal Health, who agreed to ship the trial treatment at no cost to Gaspar or Boomer's owners. MacLeod needed FDA approval to ship the medication to Illinois.

The treatment, MacLeod said, is not a cure for kidney disease. Rather, he says, it corrects the anemia.

"In people, as well as animals, it's clear that the anemia contributes to weakness, loss of energy and poor appetite. When you correct the anemia . . . energy and appetite levels often improve dramatically," MacLeod said.

Boomer received his first injection Wednesday in Gaspar's office. The cat's owners will give subsequent injections three times a week.

MacLeod said chronic kidney disease is most prevalent in cats among all companion animals. He said a recent study in the Journal of Small Animal Practice found that kidney disease is common in middle-age cats (3 to 8 years old), and that necropsies on 333 cats found the disease in 5.7 percent of the animals, similar to other studies.

Thirty-four percent of U.S. households have at least one cat.

Gaspar said cats get kidney disease for several reasons. As carnivores, they eat a high-protein diet, which is hard on the kidneys. They also produce highly concentrated urine, which taxes the kidneys, and usually drink only small amounts of water. She added that many older cats also have high blood pressure that can negatively affect kidney function.

One of the kidney's important functions is the production of a hormone called erythropoietin, or EPO, which travels to the bone marrow, where it stimulates the production of red blood cells. As kidney failure progresses, chronic kidney disease patients often develop nonregenerative anemia (decreased production of red blood cells) because of reduced EPO synthesis, MacLeod said.